Glaucoma is a disease characterized by visual field loss caused by degeneration or shedding of retinal ganglion neurons, which may lead to blindness if left untreated. Elevated intraocular pressure is one of the pathoetiologies of glaucoma, but, for example in Japan, the number of patients of glaucoma which is not associated with the elevated intraocular pressure, i.e. normal tension glaucoma, is up to 60% of the total number of the patients of glaucoma. The current therapy for glaucoma, whether drug administration or surgery, depends on intraocular pressure reduction. The progression of glaucoma may be arrested or delayed by reducing the intraocular pressure of the patients of normal tension glaucoma, but even if the intraocular pressure is reduced, no or little delay of the progression of glaucoma is achieved in some patients. Furthermore, in the first place, since the intraocular pressure of the patients of normal tension glaucoma is normal, the reduction of the ocular pressure may not be possible or sufficient. Alternatively, even in the case of glaucoma associated with the elevated intraocular pressure, sometimes the progression of glaucoma may not be sufficiently delayed or the reduction of the intraocular pressure may be difficult.
For the treatment of glaucoma, agents such as sympathomimetic agents (nonselective agonists such as epinephrine, α2 agonists such as apraclonidine), sympatholytic agents (β-blockers such as timolol, befunolol, α1-blocker such as bunazosin hydrochloride), parasympathomimetic agents (such as pilocarpine), carbonic anhydrase inhibitors (such as acetazolamide, brinzolamide), prostaglandins (such as isopropyl unoprostone, latanoprost, travoprost, bimatoprost) are used. These agents reduce the intraocular pressure.
Retinitis pigmentosa is a disease characterized by visual field loss and night blindness caused by degeneration or shedding of photoreceptor cells. The half of the cases of retinitis pigmentosa is hereditary, and the other half is sporadic. The method for treating retinitis pigmentosa is not sufficiently established.